Generally, samples for radionuclide analysis have different shapes and different chemical and physical properties. The radioactivity may be small in a large sample, or the radioactivity may be large in a very small sample. If the sample is composed of a material with high density and high atomic number, it may be difficult to measure by gamma ray attenuation.
Accordingly, in order to obtain the best possible radioactivity spectra and reliable values, the sample should be mounted on the detector of the optimum condition.
Meanwhile, to analyze gamma ray-emitting nuclides present in the sample, it is important how gamma rays penetrate through materials and how the gamma rays are detected. To meet these requirements, high purity germanium gamma spectroscopy systems (hereinafter, referred to as “HPGe”) have been widely used since such systems exhibit efficiency at low energy and excellent resolution over the entire energy range.
As the HPGe has been utilized domestically and internationally, Marinelli beakers (1 L) for filling samples therein to correspond to detectors mounted thereto have also been diversified.
Further, the recently introduced Marinelli beaker is large in size considering the diameter of the detector mounted to various HPGe products, whereby a gap between the detector and the detector-inserting portion of the lower portion of the beaker is formed, thereby causing an increase in uncertainty of the detected value. In other words, it is required to develop a correction container capable of reducing experimental error (geometric uncertainty) caused by the gap between the Marinelli beaker and the detector when the sample is mounted to the detector.
The experimental error can be expressed as the following standard uncertainty. In other words, combined standard uncertainty (UC) refers to standard uncertainty of a measurement result when the measurement result is obtained from several different inputs, and if the uncertainty factor (input quantity) is independent, the combined standard uncertainty is obtained as in the following Equation 1, by combining uncertainty (UA) obtained by statistically analyzing a series of observations and uncertainty (UB) obtained by mathematical method.
In other words, the correction container is provided in a gap, which may occur in the contact surface between the lower part of the Marinelli beaker and the detector in the process of analyzing the sample, thereby reducing not only standard deviations occurring in repeated experiments, but also calibration errors during instrument calibration, which relates to statistically analytical uncertainty (UA).Equation 1UC=√{square root over (U2A+U2B)}  [Equation 1]
In Equation 1, UC refers to the combined standard uncertainty, UA refers to uncertainty determined by observations, and UB refers to uncertainty determined by a mathematical method.